Hydraulic change-speed gear



W. B. CROFTON.

HYDRAULIC CHA APPLICATION FIL NGE SPEED GEAR.

ED .IULY18,19I9.

Patented Mar. l, 1921.

2 SHEETS-SHEET l.

W.I B. CRoFToN.

HYDRAULIC CHANGE SPEED GEAR. APPLICATION FILED ILILY I8, 1919.

1,3'7@,29@, f Patented Mar. smo

2 sHEETs- 2.

i UNITED STATES 4PA'I'ENT oFFlcE.

WILFRED BRERETON CROFTON, OF YEOVILLE, JOHANNESBURG, TRANSVAAL, SOUTHAFRICA.

HYDRAULIC CHANGE-SPEED GEAR.

Specification of Letters Patent.

Patented Mar. 1, 1921.

Application filed July 18, 1919. Serial No. 311,877.`

To au lwhom t may concern.'

Be it known that I, IVILFRED .BRERE'roN CRoFToN, a British subject,residing at 56 Harley street, Yeoville, Transvaal, Province of the Unionof South Africa, have invented certain new and useful Improvements inHydraulic Change- Speed Gears, of which the following is a specication.

rllie present inve: ,i ion relates to speed changing gear suitable formotor vehicles, of the kind in which aset of radial cylinder pumpsdriven by the engine delivers liquid to a radial cylinder motor setdriving the propeller shaft; different velocity ratios being attained byvarying the amount of liquid delivered to the motor cylinders.

n object of the invention is to provide such a construction whichaffords ample and fairly direct communication from the pump cylinders tothe motor cylinders. A\nother object is to provide for direct drive whenthe speed ratio is unity,

The invention is illustrated in the accompanying drawings in whichFigure I is a longitudinal section and Fig. II a cross section oii A, A,Fig. I.

l indicates a set of radial pump cylinders and 2 a set of radial motorcylinders,

said sets being rigidly connected by a hol-- low shaft 3, and the wholebeing mounted to revolve within a fixed casing 4. They are free thus torevolve at unity ratio, but otherwise they are held from rotation withrespect to the casing by a brake which, as shown, comprises a band 5fitted with a spring 6 which causes it togrip the drum 7. In the exampleshown there are six pump cylinders and four motor cylinders, the volumeof the former being less than that of the latter to the extent that whenall the pump cylinders are delivering to all the motor cylinders, thepropeller shaft is vdriven at second speed. rI`he next lower V* c shaftisthereafter extended at 11 axially into the shaft 3 to act as a rotarydis'- tributing valve as hereafter described. The

propeller shaft 12 is similar, being cranked at 13 to 4co-act with thepistons of the mo- Johannesburg,

tor cylinders 2 and extended at 14 to form a distributing valve.

The casing 4 is charged with -oil which is taken in by the motorcylinders at the intake 15. In order to insure the cylinders beinglproperly filled at high speeds, the oil is fed centrifugally to theintake by vanes 16 formed on the crank cheek 17. It enters the intake byway of a number of light valves 18 which automatically close outward andwhich are light enough not materially to impede the inward fiow of oil.

Each cylinder is formed with a port 19 and the ends of said ports openaround the bore of the hollow shaft 3 as appears in Fig. II. The rotaryvalve 11 is formed with a D port 20 which connects the cylin,y

der ports 19 with the intake 15 when the pump cylinders are filling, andwith a second port 21 which, when the cylinders are discharging,connects thel cylinder ports 19 and the open endedbore 22 of the valve.The rotary valve 14 of the propeller shaft 12 is similarly formed with aport equivalent to port 21 forming the left hand ter- Vmination of thelongitudinal bore 23 of said valve and connecting said bore to theintakii'ig motor cylinders. The oil is exhausted from the motorcylinders by aport 24 which delivers it to outlet orifices 25 in theshaft casing 4.

The adjacent ends vof the rotary valves 11 and 14 are separated so thatoil can pass from `the passage 22 to an orifice 26 in the 3, whence itreturns to the yhollow shaft 3. Said orifice is controlled by a sleeve27 sliding fluid tight on the outside of the shaft 3 and moved back andforth by the clutch .pedal 28. yWith the sleeve -27 fully to the left,the outlet 26 is open; all the pump cylinders 1 are short'circuited, sothat no power is transmitted to the motor cylinders and the gear is inthe neutral position.

Upon` shifting the sleeve to the right'as shown in Fig. I the outlet 26is closed. All

' oil delivered by the pump cylinders 1 to the valve passage 22 isaccordingly passed to the motor cylinders 2.

In three of the pump cylinder ports 19 are sliding valves 29l which,when in the position shown in Fig. I, cut out said three cylinders byconnecting .directly and only to the oil` reservoir ofthe casing 4. Saidcylinders therefore do not contribute to the next higher gear isreached.

Said valves 29 are actuated by a sleeve 30 sliding on the shaft 3. Thesleeve 30 is slid to right or left by a striking rod 31 actuated by ahand lever 32 engaging in a slot 33.

The next gear is unity and is attained by stopping the exhaust of oilfrom the motor cylinders and at the same time releasing the whole of thecylinder block to revolve freely. For this purpose there is provided asecond striking rod 34 having a slot 35 for the reception of the end ofthe lever 32. When said lever has thrust the striking rod 31 fully tothe left, the slots 33 and 35 are in line. The lever 32 is then movedlaterally to transfer its end from slot 33 to-slot 35 and upon itsendwise movement being continued, it thrusts the striking rod 34 to theleft. Said striking rod 34 is provided with a wedge 36 which passesbetween the ears 37 of the brake band 5,. forces said ears apart againstthel spring 6 and so releases the brake from the drum 7. At the sametime the outlet 25 is closed by the sliding sleeve 38 which is rigidlyconnected to the sliding sleeve 39 and which latter is engaged by thestriking rod 34. The oil being thus stopped 'from circulating, causesthe crank shaft 8, the pump cylinders 1, the motor cylinders 2 and thepropeller crank shaft 12 to revolvesolidly.

Reverse is attained by reversing the position of valve 14 relatively tothe propeller crank shaft 12.

The crank cheek 40 is formed integral with the valve 14 but the crankpin 13 merely seats in a recess 41 in said cheek. A spring 42 compressedbetween the rotary valves 11 and 14 normally holds said. cheek 40 intoengagement with crank pin 13. 43

is a sleeve sliding on the shaft.3 and ac' tuated by a reverse lever 44.Two arms 45 Y project from said sleeve 44v and each arm carries a pin 46which extends through al guide 47 between the motor cylinders 2. Saidpin 46 `is free to rotate but not to move endwise with regard to the arm45.- It is held in a normal angular Vposition with regard to the arm bya spring 48 and is'normally kept clear of the cheek 40 by, a spring 49.At the other end of the pin is a lateral finger 50 which can makecontact with the left hand face 51 of the crank cheek 40 and thereby,upon the sleeve being moved to the right, thrust said cheek in the samedirection. At the end of the rotary valve 14 is a clutch element 52which is yieldingly supported longitudinally by a spring 53, but whichrotates positively With said valve 14. Said clutch element is adapted toengage the correspondingly formed end 54 of the valve 11. Accordinglywhen the sleeve 43 is moved to the right, -the fingers 50 engage thecrank cheek 40 and by moving the same to the right disengag said cheekand the valve 14 from the crank pin -13 and also clutch them to therotary valve 11.- The latter valve being in rotation, it carries thevalve 14 around with it. The first small rotational movement swings upthe fingers 50 and disengages them from the face 51 of the cheek 40.This device prevents the lever 44 from being operative for morev than amoment and so prevents the valve 14 from being rotated too far. The edge55 of the cheek being beveled, the. finger slips over the same and sobecomes inoperative.` The valve 14 however is held to the right by thecrank pin 13 bearing on the plain face 51 of the cheek 40, until saidvalve has been rotated one half of a revolution7 when the crank pin 13engages in a second recess 41a, and the valve 14 is accordingly allowedto move back to the left. It then ceases engagement with the valve 11,and resumes engagement with the crank pin 13, but displaced 180Orelatively to its former position. The ports of said valve 14vareaccordingly reversed and the shaft 12 is `driven in the reversedirection from the shaft 8.

An engine starting arrangement is provided consisting of a pump 56 whichtakes oil from the interior of the casing 4 and delivers it by aconduit5 to a hollow swivel ring 58 from which it is delivered by thepipe 59 to the pump intake 15. The nonreturn valves 18 are provided toprevent such oil from passing back to the casing. 1t accordingly passesinto the pump cylinders 1 which now act as motor cylinders to drive theengine.v The pump 56 is actuated by any suitable means such as`l thehand lever 60.

A safety valve 61 opening into the casing is provided at any suitablepart of the oil circulatory system to prevent overpressure occurringtherein.

The cylinders aresurrounded by a light calsing 62 to prevent unduechurning of the o1 I claim- 1. In hydraulicchange -speed gear, thecombination of aV supporting casing. a rigid cylinder block rotatable inthe casing, and comprising a set of radial pump cylinders and a set ofradial motor cylinders, pistons ing. said means releasing said blockwhen the motor cylinder outlet is closed.

2. In hydraulic change speed gear, the combination with a supportingcasing, of a rigid cylinder block rotatable in the casing and comprisinga set of radial pump cylinders and a set of radial motor cylinders,pistons in said cylinders, a driving crankshaft to which the pistons ofthe pump cylinders are connected. a driven crank shaft to which thepistons of the motor cylinders are connected, connections for the flowof liquid from the pump cylinders to the motor cylinders, a hollow shaftrigid with the cylinder block and providing an outlet from the motorcylinders, a sliding sleeve on the shaft adapted to cover said outlet, abrake element on the cylinder block, a co-acting brake element adaptedto clutch with the rst mentioned brake element, and a manually actuatedmovable part arranged simultaneously to declutch the co-acting brakeelement and to shift the sliding sleeve to cover the motor cylinderoutlet.

3. In hydraulic change speed gear, thev combination with a supportingcasing, of arigid cylinder block rotatable 1n the casing, adjustablemeans for securing the cylinder block to the casing, said cylinder blockcomprising a set of radial pump cylinders and a set of radial motorcylinders, pistons in said cylinders. a' driving crank shaft to whichthe pistons of the pump cylinders are connected, a driven crank shaft towhich the pistons of the motor cylinders are connected, a liquidcirculatory system between the cylinder sets, and means in said systemto vary the amount of liquid delivered by the pump cylinders as comparedwith the amount of liquid received by the motor cylinders and therebyvary the speed ratio of the crank shaft.

4. ln hydraulic change speed gear, the combination with a supportingcasing, of a rigid cylinder block rotatable in the casing, adjustablemeans for securing the cylinder block to the casing, said cylinder blockcomprising a-set of radial pump cylinders and a set of radial motorcylinders, pistons in said cylinders, a driving crank shaft to which thepistons of the pump cylinders are connected. a driven crank 'shaft towhich the pistons of the motor cylinders are connected. a liquidcirculatory system between the cylinder sets, and means in said systemto short-circuit the whole of the pump cylinders and thereby electneutral gear.

In hydraulic change speed gear, the combination with a supportingcasing, of a rigid cylinder block rotatable in the casing, adjustablemeans for securing the cylinder block to the casing, said cylinder blockcomprising a set of radial pump cylinders and a set of radial motorcylinders, pistons in said cylinders, a driving crank shaft to which thepistons of the pump cylinders are connected. a driven crankshaft towhich the pistons of the motor cylinders are connected, a liquidcirculatory system between the cylinder sets. said system including ahollow shaft connecting the sets of cylinders, said sha ft heilig formedwith outlet means, and a sliding sleeve adapted to cover said outletmeans.

6. In hydraulic change speed gear. the combination with a supportingcasing. ot' a rigid cylinder block rotatable in the casing, adjustablemeans for securing the cylinder block to thecasing, said cylinder blockcomprising a set of radial pump cylinders and a set of radial motorcylinders, pistons in said cylinders, a driving crank shaft to which thepistons of the pump cylinders are connected, a driven crank shaft towhich the pistons of the motor cylinders are connected. a liquidcirculatory system between the cylinder sets, and means in said systemto render inoperative a portion of the pump cylinders and thereby effectan intermediate gear ratio.

'7. In hydraulic change speed gear. the combination with a supportingcasing, of a rigid cylinder block rotatable in the casing. adjustablemeans for securing the cylinder block to the casing, said cylinder blockcomprising a set of radial pump cylinders and a set of radial motorcylinders, pistons in said cylinders, a driving crank shaft to which thepistons of the pump cylinders are connected. a driven crank shaft towhich the pistons ot' the motor cylinders are connected, a liquidcirculatory system between the cylinder sets` and valve means in saidsystem movable to place some of the pump cylinders directly incommunication with the interior of the casin 8. n hydraulic .changespeed gear. the combination with a supporting casing, of a rigidcylinder block rotatable in the casing and comprising a set ofradialpump cylinders and al set of radial motor cylinders, pistons in saidcylinders, a driving crank shaft to which the pistons of the pumpcylinders are connected, a driven crank shaft to which 1lb the pistonsof the motor cylinders are connected, a liquid circulatory systembetween the cylinder sets, said system including an outlet from thelnotor cylinders, means movable to close said outlet. valve means insaid system movable to place some of the pump cylinders directly incommunication with the interior of the casing, a brake element on thecylinder block, a co-acting brake element adapted to clutch with thefirst mentioned brake element, an operating lever adapted upon a firstmovement -so to move the valve means in the circulatory system to renderinoperative the pump cylinders controlled by said valve means, and upona furl ther movement to close the outlet from the motor cylinders and tode-clutch the brake element.

9. In hydraulic change speed gear, the combination of a supportingcasing, a rigid cylinder block rotatablein the casing and comprising aset of radial pump cylinders and a set of iadial motor cylinders, thepump cylinders having an aggregate volume less than that of the motorcylinders, pistons for said cylinder sets, a driving crank shaft towhich the pistons of the pumpcylinders are connected, a driven crankshaft to which the pistons of the motor cylinders are connected, aliquid circulatory system whereby liquid can pass from the pumpcylinders to the motor cylinders aiidback again. said circulating systemincluding an outlet from the motor cylinders, means to close saidoutlet` said system also including means to render a portion of the pumpcylinders inoperative and further means to render all the pump cylindersinoperative, and means for making ing the cylinder block fast with thecasing, said means releasing said block when the, motor cylinder outletis closed.

1'0. In hydraulic change speed gear, a liquid reservoir, a set of radialcylinders, a hollow shaft rigid therewith, a'crank shaft rotatablerelatively to thecylinders, a rotary valve in the hollow shaftand'rotating with the crank shaft, the cylinders being formed with portsopening to the interior on the hollow shaft, and the hollow shaft beingformed with ports in connection with the liquid reservoir, a D port inthe rotary valve connecting said cylinder ports and said ieservoirports, and a second port in the valve connecting said cylinder ports to"an axial bore in the valve.

11. In hydraulic-change speed gear, the combination with a supportingcasing, of a rigid cylinder block rotatable in the casing, andcomprising a set of radial pump cylinders and a set of radial motorcylin-Y ders, pistons in said cylinders, a driving crank shaft vto whichthe pistons of the pump cylinders are connected, a driven crank shaft towhich the pistons of the motor cylinders are connected, a liquidcirculatory system between the cylinder sets,"

said' system including a hollow shaft connecting thesets of cylinders,two `rotary valves one rigid with each crank Shaft and arranged todistribute liquid passing to and from the cylinders, said valves beingseated in the hollow shaft and having open ended bores forming thepassage for How of liquid from the pump cylinders to the motorcylinders, said circulatory system including an outlet from the motorcylinders, means to close said outlet, and means for making the cylinderblock fast with the casing, said means releasing said block when themotor cylinder outlet is closed.

12. In hydraulic change speed gear, `a set of radial pump cylinders anda set of radial motor cylinders, each set of cylinders having a crankshaft and a rotary distributing valve co-aXial and rotating with thecrank-shaft, one -of said valves being adjustable with respect to itscrank shaft'to reverse the direction of rotation of the motor crankshaft.

13. In hydraulic change speed gear, a set of radial pump cylinders and aset of radial motor cylinders, each set of cylinders having a crankshaft and a rotary distributing valve vco-axial and rotating with thecrank shaft, the motor cylinder valve being adapted to be disconnectedfrom its crank shaftI spaced 180C apart, and locking by relativelongitudinal movement of said parts, yielding means tending to hold thevalve in eiigagement with its crank shaft, means for rotating the valvewhen disconnected from its crank shaft, and disconnecting means for`releasing said 'valve from its crank shaft, said disconnecting meansbeing rendered inoperative by rotation of the valve.

15. -In hydraulic change speed gear, a

liquid4 reservoir,` lapumep cylinder set, a

"closed intake for said cylinder set,out

wardly closing automatic valve means governing communication from thereservoir to liquid into said intake.

In testimony whereof I affix my signature.

WILFRED BRERETON CROFTON.

'said intake, and a pump adaptedto deliver

